Shear press back gauge



Aug. 29, 1950 R. F. DEHN 2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 11 Sheets-Sheet 1 IN V ENTOR.

BY For E DEA/N Aug. 29, 1950 R. F. DEHN SHEAR PRESS BACK GAUGE l1Sheets-Sheet 2 Filed Feb. 14. 1947 INVENTOR.

E r 0 A v F Aug. 29, 1950 R. F. DEHN SHEAR PRESS BACK GAUGE llSheets-Sheet 3 Filed Feb. 14, 1947 1M 'EN TOR.

Ear F." flew/v ATTOR NEY5 Aug. 29, 1950 R. F. DEHN 2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 11 Sheets-Sheet 5 l I M5INVENTOR. Pay F7 DEHN BY wax W1 3% iflflflm Aug. 29, 1950 I R. F. DEHN2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 11 Sheets-Sheet 6 INVENTOR.

" 4 4 0) E flE/v/N Aug. 29, 1950 R. F. DEHN 2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 ll Sheets-Sheet 7 9, 1950 R.F. DEHN 2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 11 Sheets-Sheet 8 ml HI o n/o FIG. 12

INVEN TOR. For E DEH/Y Aug. 29, 1950 Filed Feb. 14, 1947 R. F. DEHN2,520,495

SHEAR PRESS BACK GAUGE 11 Sheets-Sheet 9 Aug. 29, 1950 R. F. DEHN2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 11 Sheets-Sheet 1O IN V ENTOR. Pay F DEHN 4 7- TOR/YE Y5 Aug. 29, 1950 R. F. DEHN 2,520,495

SHEAR PRESS BACK GAUGE Filed Feb. 14, 1947 11 Sheets-Sheet 11 I I 2 V mln I, H I- 14 INVENTOR. Roy E DEH/f %1'0, 444407,, a /2f; (zihidml iatented Aug. 29, 1950 UNITED trans STATES PATENT OFFICE SHEAR PRESS BACKGAUGE Application February 14, 1947, Serial No. 728,425

28 Claims. 1

The present invention relates to shears and, more particularly, topower-operated shears provided with back gauge mechanism.

The present application is a continuation-inpart of my copendingapplication for patent, Serial No. 641,325, filed January 15, 1946, andnow abandoned.

One of the principal objects of the invention is the provision of noveland improved back gauge mechanism for power-operated shears, whichmechanism is simple in construction, inexpensive to manufacture,reliable and accurate in operation, and readily set in the desiredposition.

Another object of the invention is the provision of a novel and improvedback gauge mechanism adjusted to any desired angle with respect to theknives of the shears, and/ or can be readily moved into or out Ofoperative position.

Another object of the invention is the provision of a novel and improvedadjustable back gauge for a heavy duty shear press, which back gaugeincludes remote means for indicating the relative position of the backgauge interconnected therewith through suitable gear trains providedwith adjustable means for controlling and eliminating gear backlashwhereby the accuracy of the indicating means is substantially increased.

Another object of the invention is the provision of a novel and improvedadjustable back gauge for a heavy duty shear press of the type referredto having two indicating dials, one reading in fractions of thegraduations of the other and both geared to the adjusting mechanism forfacilitating and increasing the accuracy of the adjustments of themechanism.

Still another object of the invention is the provision of a novel andimproved adjustable back gauge of the character referred to having aneasily accessible locking means for locking the mechanism in an infinitenumber of adjusted positions.

A further object of the invention is the provision of a novel andimproved power shears of the general type employed in shops engaged inthe fabrication of metal plates and the like, and having an oscillatableupper leaf including back gauge mechanism.

A still further object of the invention is the provision of a novel andimproved power shears of the type referred to, having a movable cuttingblade and back gauge for positioning material to be sheared relativethereto, the back gauge being adjusted by an independently mountedelectric motor and movable relative to the blade and motor into and outof operative position.

The invention resides in certain constructions and combinations andarrangements of parts, and further objects and advantages will beapparent to those skilled in the art to which it relates from thefollowing description of the pre ferred embodiment described withreference to the accompanying drawings forming a part of thisspecification in which similar reference characters designatecorresponding parts throughout the several views, and in which:

Fig. 1 is a front elevational view of a poweroperated, heavy duty shearsembodying the present invention;

Fig. 2 is a rear view of the shears;

Fig. 3 is an end view of the shears, looking from the right of Fig. 1;

Fig. 4 is a sectional view approximately on the line fi-A of Fig. 1;

Fig. .5 is a fragmentary sectional view approximately on the line 55 ofFig. 4;

Fig. 6 is an enlarged View of a portion of Fig. 4;

Fig. 7 is a fragmentary sectional View on the line 1-! of Fig. 6;

Fig. 8 is a view similar to Fig. 6, but showing the back gauge raised toinoperative position;

Fig. 9 is an enlarged View of a portion of Fig. 5;

Fig. 10 is a sectional view, with portions in elevation, on the linel@-i 9 of Fig. 9

Fig. 11 is a front elevational view of a poweroperated heavy duty shearsembodying the pres ent invention, but of modified construction;

Fig. 1-2 is a rear view of the shears shown in Fig. 11;

Fig. 1.3 is a fragmentary sectional view on the line i3l 3 of Fig. 11;

Fig. 14 is an enlarged view of the dial indicating mechanism shown inFig. 13;

Fig. 15 is a fragmentary sectional view approximately on the line 15-! 5of Fig. 13;

Fig. 16 is a sectional view on the line iii-16 of Fig. 15;

Fig. 17 is a fragmentary sectional View on the line l'lli of Fig. 16;

Fig. 18 is a wiring diagram showing the control circuits for the shearsshown in Figs. 11 to 14;

Fig. 19 is a fragmentary sectional view on the line 55 of Fig. 4 showingprovision for eliminating gear backlash;

Fig. 20 is a view partially broken away of a modified construction of adial indicating and locking mechanism;

Fig. 21 is a sectional view on the line 2l2l of Fig. 20; and,

Fig. 22 is a View similar to Fig. 16 showing a a modified form of slidemember, parts of the guide therefor being broken away for clarity.

To a large extent, the shears shown herein is similar to the shearsshown and described in United States patent to William G. Wehr, No.2,397,895, and only those parts of the shears which are necessary to acomplete understanding of the present invention are herein shown anddescribed in detail. Reference to the aforesaid patent is made for acomplete showing and description of those parts of the shears not fullyshown and described herein.

Referring to the drawings, the reference chanaoter A designates a framecomprising stressresisting, plate-like end members or sid housings it,i! having aligned openings l2, it, respectively, in their front edges; acrown i l; and a bed comprising plate-like members l5, it, if, thelatter of which forms a scrap chute. The vertical plate-like member 55is located immediately to the rear of and welded to the horizontalplate-like member it, which member in addition to reinforcing the upperedge of the member It, forms a support or work table for the work. Theupper member or crown it is generally boxshaped in cross-section and hasits opposite ends welded to the side housings it, if adjacent to theirfront upper edges. Web members i, 22 welded to the interior of themember it reinforce the same and the lower ends of the members 2%, 25which extend below the rear side of the member id form supports forsuitable bearings within which a crankshaft Z3 i rotatably supported.

The shearing operation is performed by a stationary shearing knife 2%located in a cutout portion at the upper rear corner of the bed and amovable shearing knife '25 connected to the lower front edge of amovable ram or blade, designated generally by the reference character B.The movable ram or upper blade B which extends substantially from oneside of the housing to th other is of built-up construction andcomprises a longitudinally extending front plate 2%? welded to the frontends of rearwardly extending end members 2?, 28, the rear ends of whichare rotatably connected to short, shaft-lil e members 3d, 35 rotatablysupported in suitable apertures in the side housings ill, ll,respectively, for rotation about an axis eccentric to the axis aboutwhich the end members 2'5, 28 are rotatable.

The axis about which the ram or blade B is pivoted is preferablyslightly above the plane of the work supporting surface of the bed.

In addition to the front plate 25 and the end members or plates 2'1, 23,the upper blade or ram B comprises a plate 32 extending between andwelded to the end members 2?, 28 and a bottom plate 33 having anupwardly extending rear flange The front edge of the bottom plate 33abuts against and is welded to the rear side of the plate 32 adjacent tothe lower edge thereof, and the ends of the bottom plate are welded tothe end members 2?, 28. The blade assembly is reinforced by web members35, 3'5, 3?, 38, as welded to the front plates 25 and and to the bottomplate 33 and by triangular plates it, at welded to the rear side of thebottom plate 33 and the end members 2?, 28.

The front plate 2% of the blade B is inclined at a slight angle to thevertical, as clearly shown in Figs. 3 and 4, to provide clearancebetween the ram or blade B and the stationary knife when the blade isoscillated. The lower front edge of the plate 26 is cut out so as toreceive the upper shearing knife 25, which knife is held in positiontherein by a plurality of screws :35 projecting therethrough andthreaded into suitably tapped apertures adjacent to the lower edge ofthe plate 26. The heads of the screws are located in a groove in thefront face of the shearing knife and are countersunk so as not tointerfere with the oscillation of the movable blade B. The lower edge ofthe plate 26 is inclined lengthwise so that th knives will effect a trueshearing action.

The front end of the ram or movable blade B is supported and the entireblade assembly is adapted to be oscillated about the shafts 35, 32 bypitmans it, ll, the upper ends of which are operatively connected toeccentrics on the crankshaft 23. The lower ends of the pitmans areconnected to short shafts fixed in opposite ends of the blade B. Thecrankshaft 23 is rotated to reciprocate the movable ram or blade B by anelectric motor 8 adjustably secured to the back of the crown hi andoperatively connected to the crankshaft by means including a frictionclutch and brake operated in such a manner that when the treadle as isdepressed and immediately released, the crankshaft makes one completerevolution but will continue to rotate as long as the foot pedal isdepressed. As shown, the weight of the movable blade B iscounterbalanced by adjustable compression springs, one at either end ofthe ram, located within tubular housings El, 52 flXd to the crown memberid.

The shears shown also include a plurality of spring-loaded, hold-downdevices 53 detachably bolted to the lower edge of a hold-down plate 5suspended from the forward arms of bell crank levers 55, 55 pivotallyconnected to the plates 23, 2|, the rear arms of which levers areprovided with rollers adapted to engage cams on the crankshaft 23. Thelevers 55, 56 are continuously urged in a clockwise direction, as viewedin Fig. 3, to engage the rollers thereon with the cams on the crankshaftby suitable compression springs 5f interposed therebetween and the topof the crown member E4. The lower part of the hold-clown plate 5 isconnected to the side housings ill, H by links 5 59, one at either sideof the hold-down plate, pivotall connected to the hold-down plate and tothe side housings lil, H.

In order to facilitate the locating of material to be cut, the shearsshown comprise back gauge mechanism carried by the movable ram or bladeB and designated generally by the reference character C. The back gaugemechanism includes a stop proper in the form of a transversely extendingbar til against which the material to be cut is adapted to abut so as tolocate it in a desired position with respect to the shearing knives. Thebar Bil is detachably connected, as by bolts 64, to a downwardlyprojecting flange 62 of a transversely extending angle iron 63. Shims 64surrounding the bolts 8! and interposed between the bar 66 and theflange 62 provide means for adjusting the bar relative to the angle iron63. This construction makes it possible to maintain a true or straightsurface for the work to abut against. Opposite ends of the angle iron 53are pivotally connected by a pair of bolts 65, 6% to I-bolt-shapedmembers G'i, 68, the heads of which are located adjacent to the forwardends of slides 79, H movably supported by pairs of guides l2, l3 and M,55 located underneath the ram or blade proper and extending fromadjacent to the front end of the blade to approxiinately the pivots 38;.3| The members: 61, 68 include rearwardly extending, cylindrical shankportions-which project throughsuitable apertures in the slides iii, H,Jam nuts, such as B'la, on the rear threaded ends of the shank. portionsof the members 6?, (it and which. engage opposite sides of downwardlyextending flanges or projections on the slide-s it, H, see Figs. 6; 7and 8 provide means for adjusting the members El, 68, and hence the stoptil, relative to the slides 16; H, respectively, thereby facilitatingthe location of the stop 60 with respect to the shear knives for a givenposition of the slides.

If the adjustment effected by the jam nuts is considered unnecessary,the angle iron 63 may be directly bolted to an integral extension on theslides as clearly shown in Fig. 22, reference to which in greater detailwill hereinafter be made.

The guides i2, it are spaced with respect to each other and the slide E6is positioned therebetween with suitable projections it, '5? on oppositesides thereof engaging within suitable grooves 83, d! in the adjacentfaces of the members i2, respectively. The slide it is supported in theguides T4, i5 in a similar manner. The forward ends of the guide members12, i3 and Hi, 35 are pivotally connected toa longitudinally'extendingshaft 82 rotatably supported by brackets 83, 8t connected by bolts 8t,3%, respectively, to the underside of the plate The brackets 83, E ihaveforwardly extending bosses 87, 88, B9, 96, respectively, within which.the shaft 82 is rotatably supported by antifriction bearings and theforward ends of the guides are pivotally supported on the outer races ofthe same bearings. The rear ends of the guides 22, T3 and 'Hl, K5 areconnected together and held in predetermined spaced relation by members9!, Q2, respectively, welded thereto.

The slides it, I! have upwardly extending portions 93, 9 5,respectively, provided with threaded apertures through which lead screws95, 96, respectively, project and through the medium of which the slidesare adapted tobe moved. The rear parts of the projections 93, 9d arespaced from the main portions thereof by grooves and are adapted to bemoved relative to the projections proper by suitable screws. Theconstruction is such that backlash or lost motion between the leadscrews and the slides can be eliminated. The rear ends of the leadscrews 95, 96 are rotatably supported in the members lit, 2 and theirforward ends which are rotatably supported by antifriction bearings $9,99 in members 91, 38 welded to the forward ends of the guide members i2,13 and 'M, "5, respectively, are provided with beveled gears Hi3, Nil,in mesh with beveled gears I02, 6%. The antifriction bearings 99, 99'take the axial thrust of the beveled gears lbil, ml, respectively, andif desired provision can be made for axially adjusting the bearings ea59 in their supporting members 97, 98 for controlling clearance betweenthe gear teeth and eliminat-= ing any backlash or other free playtherebetween. An embodiment of the invention incorporating such aprovision is shown in Fig. 19, reference to which will hereinafter bemade. The gear W3 is keyed to a short sleeve lii i fixed to theleft-hand end of the shaft 82, as viewed in Fig. 5, and the gear W2 iskeyed to a short sleeve Hi5 surrounding the shaft 82 and rotatablethereon. The shaft 82 projects tothe right, as viewed in Fig. 5, beyondthe end member 2'! of the ram and through the cut-out portion iii of theside housing. The pro- 6 jecting end of the shaft is providedwith: ahand crank. me for. manually rotating the same. Alternatively, theshaft. 32 may be motor driven, if desired, as. will be. hereinafter morefully described,

The sleeve let to which the gear W2 is fixed is adapted: to beselectively connected to the shaft 82 so that the lead screws 95, 96 maybe" simultaneously rotatedv or the lead screw to rota-ted alone, by asuitable clutch designated generally by the reference character D. Inthe embodiment shown, the driven element of the clutch D comprises aflange I61 formed integral with the right-hand end of the hub of thegear Hi2 and provided with a plurality of axially projecting pins maadapted to engage within suitable apertures iii! in the driving elementHll which in turn is splined to the shaft 82 to the right of the gearIE2. The driving element iii of the clutch. D is continuously urgedtoward the left, as viewed in Fig. 5, to engage the pins. N3 in theapertures Hil by a compression spring [r2- surrounding the shaft 82 andinterposed between the right-hand end of the driving element Hi and acollar 9 ifi'adjustably connected to the shaft 82 by a setscrew. Thedriving element li'l has an. external groove He within which a yokemember H5 engages, and through the medium of which the driving elementcan be moved toward the right to disconnect the same from the drivenelement of the clutch. The member H5 is connected to a rod M6:projecting through the aperture i2 in the side housing [0. The rod HE isslidably supported in a housing H? bolted to the outside of the endplate 2?, which housing also supports the right-hand end of the shaft82, and a member H8 welded or otherwise secured to the underside of theplate 33. The end of the rod lit which projects beyond the side housingit is provided with a hand grasp for facilitating manual manipulation ofthe rod.

The front ends of the guide assemblies, including the guide members i2,i3 and M, '35, are supported for pivotal movement about the shaft 232,as previously explained, and the rear ends thereof are adapted to beselectively raised or lowered to move the stop 6!] out of or intooperative position. As shown, the rear ends of the guide members l2, it,it, 15 are connected by a plurality of. pivoted. links i253, i2l, E22,[23 to levers Hi l, E25, 525, m, which levers are in turn pivotallyconnected to rearwardly extending arms ltd, 53!, M2, i333 formedintegral with brackets 134, I35 bolted to the rear side of the flange 35 of the plate 33. The links we to M3 are connected to the levers A24 to{21. intermediate their ends and the free. ends of the levers H24 to is?are connected by a longitudinally extending rod Hi6 welded thereto. Theconstruction such that as the levers 2 3 to [2? are rotated about theirpivotal connections with the arms led to 33 upon manipulation of the rodI35 by an operator, the pivots which connect the links i253 to lit withthe levers i2i to E2? are raised from the position shown in Fig. 6 wherethey are below the pivots which connect the levers 52% to iii with thearms [3b to 133, to the position shown in Fig. 8 where they are abovethe pivots referred to. The result is that the rear ends of the guideassemblies are raised so as to move the stop it above the path ofmaterial being sheared, assuming that the stop 56 has first been movedto or adjacent to its rear position. Material being sheared or to besheared is shown in dot-dash lines and designated M in Figs. l, 6 and 8.The

7 brackets I34, l35 include pairs of arms I31, I 38', I39, Hill whichproject downward along opposite sides of the guide members I2, 13 and il, I5, respectively, and assist in guiding the rear ends of the latteras they are raised and lowered.

The shears shown also comprise indicator means, designated generally bythe reference character E, for showing the setting of the back gauge orfor assisting in properly setting the back gauge to the desiredposition. The indicating means shown comprise an annular dial Hli havinga scale i 32 thereon reading or graduated in sixty-fourths of an inch.The dial l ii is an integral part of a tubular sleeve-like member hi3surrounding the shaft 82 adjacent to the hand crank M5. The sleeve M3 isfixed to the shaft 82 by a pin EM and comprises in addition to the dialit! a worm M and a knurled flange I46 adapted to be engaged by theright-hand end of a spring-pressed lever i i! pivoted by a pin MS to thehousing ill. Ihe lever MT is continuously urged in a direction to engagethe right-hand end thereof with the knurls of the flange I 55 by aspring I58, located in a suitable aperture in the housing l i? andpressing against the left-hand end of the lever Ml, as viewed in Fig. 9.The lever Hi1 normally maintains the shaft 82 in any position to whichit is turned by the hand crank 56. A handle I55 on the lever it?provides means for raising the lever from engagement with the flange MEand in turn freeing or releasing the shaft 82 so that it may be rotated.If accuracy greater than that obtainable by the lever i s'i engaging thenecessarily slightly spaced knurls of the flange I66 is desired, lockingmeans may be provided for securing the shaft 82 in an infinite number ofpositions, as will be more fully hereinafter described with reference tothe modification of the invention shown in Figs. and 21.

The scale M2 is adapted to cooperate with a zero or dead line E52 on aring 953 rotatably supported on an annular portion 554 of the housingIll adjacent to the dial MI. The ring ass is adapted to be secured inany position to which i it may be adjusted by a thumb screw I555. Theright-hand end of the housing i i? adjacent to the ring 53 is providedwith a member E56 having a scale it? thereon graduated in onethousandthsof an inch, which member is adjustably connected to the housing by aplurality of screws 558 that project through elongated slots in the endsof the member 555. The construction is such that when the shearingknives 24, are set at zero clearance with the back gauge proper abuttingthe rear side of the stationary shearing knife E4, the zero graduationsof the scales M2, 55? and the zero or dead line graduation 252 can allbe aligned. The adjustability of the ring i533 incorporates compensatingmeans into the indicator mechanism for various shearing knife clearancesettings by merely resetting the zero line H2 at the position on thescale corresponding with the clearance between the shearing knives inthousandths of an inch. If greater accuracy of the position of the backgauge as indicated by the scale M2 or if increased ease of adjustment ofthe back gauge or both is desired, the dial It! may be separatelymounted on the housing ill and geared to or otherwise operativelyconnected with the shaft 32, as will be more fully hereinafter describedwith reference to the modification of the invention shown in Figs. 20and 21.

The worm I is continuously in mesh with a Cir worm wheel I60 formedabout the circumference of the member iBI, which member includes anintegral shank I62 through the medium of which it is rotatably supportedin a boss I63 forming a part of the housing I H. The member I6I includesan annular dial I64 projecting to the front of the boss I83, which dialis provided with an inch scale IE5 adapted to cooperate with a zero mark566 on the boss N53. The lead of the screws 95, @ii is such that uponeach rotation of the shaft 82, the back gauge moves one inch and theratio of the worm and worm Wheel I45, I66 is such that upon the dial 564making one revolution, the back gauge is moved forty-eight inches, whichhappens to be the full travel of the back gauge shown. Alternatively,lead screws of any other suitable pitch or gears of any other suitableratio may be employed and the dials graduated accordingly to give anydesired reading or indication.

It is believed that the operation of the device will be apparent fromthe foregoing description thereof. In order to set the back gauge inposition to shear a strip from a plate or sheet, it is merely necessaryto adjust the annular member i53 so as to set the zero mark I52 at theknife clearance being employed and thereafter rotate the hand crank theuntil the desired setting is read upon the scales I 52, I65, havingfirst removed the lever M1 free of the knurled flange M5. If it isdesired to set the back gauge in an inclined position with respect tothe length of the shearing knives, the hand crank IE8 can be rotateduntil the lead screw has moved the right-hand end of the gauge to thedesired position. Thereafter the clutch D is operated to disengage thedrive to the lead screw 95 whereupon the crank I96 can be 0perate d torotate the lead screw 95 to move the left-hand end of the gauge to thedesired postion.

In the embodiments of the invention shown in Figs. 11 to 22, duplicateparts to those of Figs. 1 to 10 are designated by the same referencecharacters and similar parts are designated by the same referencecharacter with a prime mark added. Referring more specifically to theembodiments shown in Figs. 11 to 18, an electric motor lid is employedfor actuating the shaft 82 and adjusting the transversely extending bar69 of the back gauge to the desired position with respect to theshearing knives. ihe electric motor Hi3, which is preferably of thealternating current, reversible, two-speed type, actuates a verticallyextending shaft I'l2 through a worm and pinion gear speed reducingmechanism I13, which shaft has keyed to its lower end a beveled gear I'Mcontinuously in mesh with the beveled gear EM. As shown, the motor H5and a housing IEB for the reducing gear mechanism H3 are fixedly mountedon the upper surface of the bottom plate 33' of the movable blade or ramB, with the lower end of the shaft E72 extending through a suitableaperture therein. The entire assembly reciprocates or oscillates withthe upper blade or ram B.

The motor I10 is shown positioned intermediate the web members 35', 31.The armature shaft of the motor is parallel to the bottom plate 3' butangularly disposed relative to the 1ongitudinal length of the upperblade or ram B and extends through a suitable aperture in the web member36'.

The beveled gear 462 is continuously in mesh with the beveled gear 800which actuates the lead screw 95 and is keyed to the shaft 82 such thatrotation of the vertical shaft M2 actuates both lead screws 95, '96simultaneously, and in turn the transversely extending bar Bil. Ifdesired, a clutch mechanism similar to that shown at :D in Fig. 5 :couldbe provided whereby the transversely extending bar 56 could be angularlypositioned relative to the shearing knives in the same manner asdescribed with reference to the preferred embodiment.

Indicator means designated generally :by the reference character F foraccurately indicating ,the position of the back gauge relative to theshearing knives is shown positioned at the upper end of the verticallyextending shaft H2 in a position slightly below and back of the lowerfront edge of the crown l4 and above the upper edge of thelongitudinally extending front plate 26, .the upper edge of which hasbeen lowered from that shown in the preferred embodiment to provideclear visibility of the indicator means. The indicator means F showncomprises a housing member H8 fixed against rotation .by a suitablebracket H9 attached to the upper edge of the longitudinally extendingfront plate '26, an annular dial I 80 having ascale t8! thereongraduated or reading in Baths of an inch, which dial is keyed to theshaft 112, and a second annular dial 182 having a scale H33 thereongraduated or reading in inches, which dial is driven or rotated from theshaft ill '2 through a suitable worm and pinion .gear arrangement i8 3positioned within the housing I18. As shown, the 56. scale till on thedial illll is adapted to co operate with a zero or dead line I86suitably inscribed on the portion of the housing i'iil adjacent thereto.If desired, suitable means for compensating for the various shearingknife clearance settings can be provided similar to the compensatingmeans shown in the preferred em bodiment.

The inch scale W3 is adapted to cooperate with a zero or dead line 188suitably inscribed on the portion of the housing till adjacent there to.The scales 'ltll, [83, the gear ratio of the worm and pinion wheel drivefor the annular dial M2, the gear ratio of the gears FM, i 62", llilll,the gear ratio of the gears W3, Wit, and the lead of the lead screws 95,96 are preferably all so proportioned that corresponding movements ofthe transversely extending bar '69 are accurately indicated on theindicator lmeans.

normally engaged disc brake (not shown) incorporated in the motormounting and electrically disengaged when the motor i l-ll is energizedis provided such that once the transversely l extending bar til has beenpositioned by suitable "rotation of the motor llt and the motordeenerglzed, "the Eli will remain locked in such position.Alternatively, the worm and pinion gear speed reducing mechanism M3 forthe mo tor l-lil may be of the self-locking type.

With the construction shown, the em mechanism F is positionedimmediately behind the front plate 26' is readily visible from the troutof the shears where the operator normally stands and, as shown in Fig.11, where the corn trol box 5% for controlling the motor lid is located.Also, the backlgau'ge :is rea'dily movable relative to zthe'inotor l idand the blade B" to and from its operative position by raising andlowering the rear ends of the guides it, H sand :12, E3, the forwardends being pivoted to and supported by the shafteZ.

FIR-he motor ill-t ispreferably a two-speed, threephase, alternatingcurrent, squirrel-cage type,

electric motor having a high speed field coil Winding l9!) and a lowspeed field coil winding l9l. The disc brake above referred to "has anelectrically energized three-phase electrical actuating coil winding 192which is energized simultaneously with either the high speed fieldwinding I90 or the low speed field winding 91 to release the disc brakeand permit rotation of the motor armature.

The starting, stopping, direction of rotation, and speed of the motor noare controlled by suitable electric switches, which are preferably ofthe push button type, each having a pair of normally open and a pair ofnormally closed contacts. In the embodiment shown, provision is made forrotating the armature of the motor Hill to move the backgauge mechanismforward at either a fast or slow speed, but for moving it backwards atonly a single'rhigh speed. The :electric switches for controlling themotor are shown mounted on the hold-down plate 5% of the shear press ina suitable control box I94, which switches comprise a forward slow pushbutton switch H95, a forward fast push button switch tilt, and a reversefast push button switch Nil. The control circuits for these push buttonswitches are preferably so interlocked such that if more than one isdepressed the motor field coil windings will not be energized. Limitswitches Hid, W9, each having a pair of normally closed contacts, aremounted on the guide -12 at the rear and forward ends thereof,respectively, and are so positioned thereon as to have their actuatingarms engageable by the upwardly extending portion 93 on the slide Hi.The limit switches, which may be adjustably positioned on theguide 12,are so connected into the control circuits such that if one limit switchshould be actuated to stop further movement of the back gauge mechanismin that direction, the motor Ill) may still be energized for driving theback gauge mechanism in the opposite direction. Bypass switches may beprovided for one or both limit switches.

Referring to the circuit diagram shown in Fig. 18, the field coilwinding of the motor Ill! and the disengaging coil winding for the discbrake are energized from a suitable source of three-phase alternatingcurrent 2M, which source continuously maintains energized alterhatingvoltage supply buses 2M, 2832, 2% The push button switches and theoperating relays associated therewith are preferably energized at arelatively low voltage through a step-down type transformer 204 havingits primaryfilld connected. across the supply bus wires 262, 283. Thesecondary 2% of the transformer 2% may supply any desired suitablevoltage at its terminals for actuating the control relays to be referredto. Relay FS when energized completes energization circuits to the slowspeed coil winding if of the motor it "ill. Relays FF, RF when energizedcomplete energization circuits to the high speed coil winding use, thephase of the voltage for the relay RF being opposite to that for therelay FF. Each of the three relays when energized complete energizationcircuits to the brake actuating coil winding I 92.

Assuming it is desired to rotate the armature of the motor lit? in aforward direction so as to drive the back gauge mechanism forward and ata low speed, the forward slow push button switch lflll is depressedcompleting a circuit from the wire 29'! connected to one terminal of thetransformm secondary 2%, through the normally closed contacts of thelimit switch 599, wire 2%, the now closed normall open contacts of thepush button switch Hi5, wire 2%, the normally closed contacts of theforward fast push button switch 5%, wire 2%, the actuating coil of relayFS, and thence through wire 25 l to the opposite terminal of thesecondary 2% of the transformer 2M. Energization of the actuatin coil ofthe relay FS closes the normally open contacts PS3, PS2, PS3, FS l, PS5thereof. Closing of the normally open contacts FSA, F65 completes acircuit from the wires EM, 282 to the wires 2H5, Elli, respectively,which wires are connected as shown to the brake winding 92 fordisengaging the disc brake supported in the motor mounting. Closing ofnormall open contacts FSI, FSZ, F83 completes a circuit from the wiresElli, 2&2, 203 to the wires 2l2, M3, 2 M, respectively, thus energizingthe slow speed field coil winding 59! of the motor l'lfi. Release of theforward slow push button switch L95 de-energizes th relay FS and thecontacts thereof return to their normally open position.

Assuming it is desired to drive the back gauge mechanism in the samedirection but at a greater rate of speed, the forward fast push buttonswitch i9 5 is depressed, completing a circuit from the wire 288, theenergization of which was previously traced, through the now closednormally open contacts of the push button switch 5%, wire 2H5, thenormally closed contacts of the push button switch 33?, wire 2 l 9, andthence through the actuating coil of the relay FF to the wire 2! l.Energization of the actuating coil of the relay FE closes its normallyopen contacts FFi, FFZ, FF3, FFG, FFE. Closing of the normally opencontacts FFil, FFc completes a circuit from wires 26!, 282 to the wires2M, 25 5, thus energizing the brake Winding 592. Closing of the normallyopen contacts FF! FPS completes a circuit from the wires Bill, 232, 2%to the wires 222i, 222, 223, respectively, thus energizing the highspeed field coil winding ass on the motor llll, causing the armature ofthe motor are to operate at a high speed. Release of the forward fastpush button switch ass de-energizes the actuating coil of the relay FF,thus de-energizing the windings 59G, i935, re-engaging the disc brakeand de-energizing the motor Hi It will be noted that 'as the back gaugemechanism reaches the desired front limit of its travel, the upstandingportion 3 engages the actuating arm of the limit switch 5 thus openingits normally closed contacts and de-energizing the wire 29% which servesas a common energizing bus for both the relay ES and the relay FF.

Assuming it is desired to move the back gauge mechanism to the rear, thereverse fast push button switch lQl i depressed, completing a circuitfrom the wire through the normally closed contacts of the limit switchH38, wire $225, the now closed contacts of the reverse fast push buttonswitch 59?, wire the normally closed contacts of the forward slow pushbutton switch E95, wire 22?, and thence through the actuating coil ofthe relay RF to the wire 2M. Energization of the actuating coil of therelay closes the normally open c ntacts RFl, RFZ, RFii, RFEB thereof.Closing of the normally open contacts RF l, RFd completes a circuit fromthe wires 2 3E, to the wires H5, 255, respectively, with the results aspreviously indicated with reference'to the closing of contacts FSQ, F55,and

Closing of the normally open contacts RFi, RF2, RFB completes a circuitfrom the wires 292, 253, 2E3! to the wires 22!, 223, 222, respectively,with the results as previously indicated with reference to the closingof contacts FSi, PS2, F83, with the exception that the phase of thealternating current voltage applied to the high speed field coil winding2% has been switched such as to cause the armature of the motor llfl torotate in the opposite direction. He lease of the reverse fast pushbutton switch Hi? de-energizes the actuating coil of the relay RF andthus the windings 925i, l9i. Should the upstanding portion lilt of theslide l0 engage the actuating arm of the limit switch Hi8, the normallyclosed contacts th reof will be opened, thus ale-energizing the wire 225and preventing further energization of the motor llil to drive the backgauge mechanism in that direction.

Referring to the embodiment of the invention shown in Fig. 19, means areprovided for adjusting the beveled gears of the back gaug drivemechanism relative to each other so as to eliminate any clearancebetween the gear teeth and, correspondingly, any backlash or other freeplay therebetween whereb the accuracy of the means for indicating theposition of the transversely extending bar till relative to the shearingknives may be substantially increased. Only a fragmentary view showingthe beveled gear mechanism for actuating the lead screw is shown,although it will be appreciated that the adjusting means can be andshould preferably be provided for all the gears in the entire back gaugemechanism, As previously described, the beveled gear ifiil is pinned orotherwise suitably fixed against rotation relative to the lead screw 95and is in mesh with tr e beveled gear m2 keyed or otherwise fixed to theshort sleeve h 5 surrounding the shaft 82 and rotatable thereon.

The forward end of lead screw 95 is rotatably supported in theantifriction bearing 99 supported in a suitable opening in a plate 9'!extending transversely between and suitably fixed to the guide membersl2, "4-3. The antifriction bearing 99 is shown rigidly fixed againstaxial movement relative to the lead screw 95 but axially adjustable inthe plate Q! by means of an adjusting sleeve 23G surrounding the leadscrew Q5 and threaded in the plate 9? to the rear of the antifrictionbearing 99. The sleeve 239 abuts against the rearmost edge of theantifriction bearing 99 whereby axial movement of the sleeve 238 willmove the antifriction bearing 59 and the beveled gear l 6!] in an axialdirection toward the beveled gear 582, eliminating any clearance betweenthe gear teeth thereof. Suitable slots 23E in the rear end of the sleeve230 are provided for engagement by a suitable adjusting tool. The sleeve236 may be fixed in any relative adjusted position by any suitable meanssuch as a setscrew 233 threadably engaged in the plate ii? and adaptedto force a soft copper plug 234 against the threads of the sleeve 23!).

Referring to the modifications of the invention shown in Figs. 20 and21, provision is there shown for locking the shaft 82 in an infinitenumber of relative positions as well as actuating the 64ths indicatingdial in such a manner as to give increased accuracy of indication and anincreased ease of positioning the transversely extending bar as relativeto the shearing knives. For fixing the shaft 82 in an infinite number ofadjusted positions, a friction type lock designated generally at G andactuated by a hand wheel 236 is provided. While the friction lock maytake a number of different forms, in the embodiment 173 of the inventionshown the lock comprises a pair of aligned spaced sleeves 23?, .238disposed at opposite sides of the shaft 82 andadapted to be moved intoclamping engagement there-with. nsshown, the sleeves 231, 238 areslidably mounted in anaperture in the housing ill on an axis transverseto and spaced slightly from the longi tudinal surface of the shaft 82. Athreaded shaft 248 keyed or otherwise fixed to the hand wheel .236extends through a central opening in the sleeve 2.38 and isthreadablyengaged in a threaded opening in the sleeve 23?. Preferably the sleeves.231, 238 have arcuate surfaces for fric .tionally engaging the surfaceof the shaft 8-2. Rotation of the hand wheel 23% in one direction movesthe sleeve members 231, 238 towards each other and into frictionalclamping engagement with the surfaces of the shaft 82.

The modified indicating means shown cornprises an annular dial i l!having a scale M2 thereon reading orgraduatcd in 64th.; of an inch. Thedial Ml is rotatably supported on a suit-- able :boss 252 formedintegral with the housing -lill', the axis of which boss is spaced fromand parallel to the axis of the shaft 82. M! has suitable gear teeth 243on its outer circumference which mesh with suitable gear teeth 1244provided onthe right hand end of the sleeve M3 rotatable with and fixedagainst rotation relative to the shaft 82' by the pin its. Preferablythe ratio of thenumber of gear teeth 244 to the number of gear teeth 2%is 1 to 2, such that forevery :two revolutions of the shaft 82 the dial.Hll will make one revolution. The gear ratios Of'the gears H98, H32,the gears Hi3, Hid, andthe lead of the threads of the lead screws 95, 96are such that the transversely extending bar Ell moves one-half inch forevery revolution of the shaft 82. If desired, the ratio of the number ofgear teeth 2 34 to the number of gear teeth 243 could be made greater orsmaller to permit any desired ratio of movement between the revolutionsof the shaft 82 and the linear movement of the transversely extendingbar 6%, while still maintaining the spacing of the graduations of thescale I 42 as shown. A cover plate mill is .fixed on the outer or righthand end of the boss 242 by a threaded bolt extending into theend of theboss .262 and holds the dial Ml on the boss :while at the same timeproviding a guard protecting the gear teeth 2&3, .2 35. A vernier scaleand means for compensating for the various shearing knife clearancesettings similar to that described with reference to the preferredembodiment are also shown.

The construction and operation of the dial Hi l, which dial is providedwith an inch scale, is identical to that shown in the preferredembodiment with the exception that the spacing of the indicia on theinch scale or the gear ratio between theworm M5 and the worm wheel teeis varied such as to compensate for the change in linear movement of thetransversely extending bar Gil for :each revolution of the shaft whichhas been made possible by driving the dial ldi from .the shaft 82through a suitable gear mechanism.

In the modified construction shown in Fig. 22, the guide 72 of the backgauge mechanism is broken away to show more clearly a slide 'lii'actuated in a fore-and-aft direction by the lead screw as. The forwardend of the slide in is pivotally connected directly to the end of theangle iron 63 by a suitable 'bolt'tfi such that the angle iron 53 may bepivoted relative to the slide FIB" if desired, but is otherwise fixedrelative The dial thereto. The upwardly extending portion 93 '1 isprovided with a threaded.aperture through which the .lead screw 95projects. A backlash or lost motion take-'up'iplateldfi :havinga'threaded aperturefor receiving the leadscrew 95 is slightly spacedfrom the right hand end of the upwardly extending portion '93 andadjusted relative thereto by adjusting (bolts 2159. The bolts 259 aretightened so thatall lost motion or backlash is eliminated. .As shown,the transversely ex tending bar Ell has been eliminated and thedownwardlyextending'fiange ofthe angle iron'63 is machined straight :andtrue and is used as an abutment orstop for the material to be out.

From the foregoing, it will be apparent that the objects .of theinvention heretofore enumerated and others have been accomplished andthat there has been provided a novel and improved shears comprising backgauge mechanism which can be readily set to the desired position ormoved to an inoperative position, if desired. While the preferredembodiments of the invention have been described in considerable detail,the invention is not limited .to the particular constructions shown andit is my intention to hereby cover :all adaptations, modifications anduses thereof which come within the practice of those skilled in the artto which the inventionrelates and the-scope of the appended claims.

Having thusdescribed my invention, I claim:

1. In shears of the character described, the combination of a movableblade adapted to have shearing "knife connected to the front thereof forcooperation with a stationary shearing knife, a guide member connectedtosaidblade, an abutment member=cperatively connected to guide memberforinovementtoward and'frorn'the front of said blade and normallyprojecting in the path ted between of work to be sheared as it i 12knives, andoperating mean in'ent member adapted to move member relativeto said blade to position at one side of said tain said member in saidino -..r ative position.

2. In ears of the character described, the combination of ainovableblade adapted to have a shearing'knife connected to the front thereoffor cooperation with a stationary shearing knife, a guide member havingone end pivotally connected to said blade, an abutment member suppcrtedby said guide member for movement toward and'from the front of saidblade nor mally projecting in the path of work to be sheared as it isinserted between said knives, and operating means *for said guide memberadapted 'to rotate the same about pivotal connection with said blade tomove said abutment member to an inoperative position at one side of saidpath.

3. In shears of the character described, the combination of a movableblade adapted to have a e'hearing knife connected to the front thereofcooperation with. a stationary shearing knife, a guide member having itsfront end pivotali'v connected to said blade, an abutment membersupported by said guide member for movement steward and from the frontof said blade and 22011113 113 projecting in the path of work to besheared as it is inserted between said knives, and operating means forsaid guide member adapted to rotate the same about its pivotalconnection with said blade to move said abutment member to aninoperative position at one side of said path.

a l. In :shears of the character described, the

for said abutment inoperative i311 and. to maincombination of a housingadapted to support a stationary shearing knife, a movable blade adaptedto have a movable shearing knife connected to the front thereof forcooperation with said stationary shearing knife, means for adjusting thehorizontal clearance between said stationary and movable shearingknives, a guide member connected to said blade, an abutment membersupported b J said guide member for movement toward and from the frontof said blade, said abutment member being adapted to project in the pathof work to be sheared as it is inserted between said knives, operatingmeans for moving said abutment member toward and from the front of saidblade, and means adjacent to the front of the shears for indicating theposition of said abutment with respect to the cutting edge of thestationary shearing knife, the last-mentioned means including a portionsettable in accordance with the adjusted clearance between said kniveswhereby the said indieating means is adjustable to afford an accurateindication of the position of said abutment for any selected clearanceof said knives.

5. In shears of the character described, the combination of a housingadapted to support a stationary shearing knife, a movable blade adaptedto have a shearing knife connected to the front thereof for cooperationwith said stationary shearing knife, means for adjusting the clearancebetween said stationary and movable shearing knives, a guide memberconnected to said blade, an abutment member supported by said guidemember for movement toward and from the front of said blade, saidabutment me1nber being adapted to project in the path of work to besheared as it is inserted between said knives, means for indicating theposition of said abutment member with respect to the cutting edge ofsaid stationary shearing knife, said lastnamed means including mechanismfor compensating for different knife clearance adjustments.

6. In shears of the character described, the combination of a movableblade adapted to have a shearing knife connected to the front thereoffor cooperation with a stationary shearing knife, a pair of guidemembers connected to aid blade and extending rearwardly of said knives,a pair of slides supported by said guide members for movement toward andfrom the front of said blade, an abutment member carried by said slidesand adapted to project in the path of work to be sheared as it isinserted between said knives, operating means common to both of saidslides for moving the same relative to said guide members, saidlast-named means including mechanism for selectively rendering saidmeans inoperative to move one of said slides whereby the other of saidslides may be moved by said means independently of the said one slide.

7. In shears o the character described, the combination of a movableblade adapted to have a shearing knife connected adjacent to the frontthereof for cooperation with a stationary shearknife, a pair of guidemembers extending rearwardly of th front of said movable blade and 11..ring their front ends pivotally connected to said movable blade, a pairof slides supported by said guide members for movement toward and fromthe front of said movable blade, an abutment member carried by saidslides and adapted to normally project in the path of work to be shearedas it is inserted between said knives, operating means for rotating saidguide members about their frcnt pivotal connections with said movablelade for moving said abutment member to an inoperative position at oneside of said path, and operating means common to both of said slides formoving the same relative to said guide members, said last-named meansincluding clutch mechanism whereby one of said slides may be movedindependently of the other.

3.111 shears of the character described, the combination of a housingadapted to support a stationary shearing knife, a movable blade to havea shearing knife connected adjacent to the lower front edge thereof forcooperation with said stationary shearing knife, means for ting theclearance between said stationary and movable shearing knives, a pair ofguide members movably connected to said movable blade and extendingrearwardly of the front thereof, a pair of slides s'ipported by saidguide members for movement toward and from the front of said movableblade, abutment member carried by s id slides and adapted to normallyproject in the of wo k to be sheared as it is insert-ed between said klves, means for raising said guide members whereby said abutment membermay be moved to an inoperative position said path, and means includingmechanism whereby one of said slides may be moved independently of theother for moving said slides relat to guide members.

9. In shears of the character described, the combination of a housingadapted to support a static y shearing is, a movable blade 'i/B'Cl tohave movable shearing knife conl thereto awacent to the lower front edgethereof for coop" ation with said stationary shea ing knife, a pair ofguide members extending rearwardly of the front of said movable bladeand having their front ends pivotally connected to said movable blade, apair of slides supported by said guide members for movement toward andfrom the front of said movable blade, an abutment member carried byslides and adapted to normally project in the path of work to be shearedas it is inserte b tween said knives, operating means for said gui .emembers adapted to raise the rear the and move said abutment m" er to aninoperative position above said pat l, means for indicating the positionof abutment member with respect to the cutting edge of said stationaryshearing knife, and means common to both of said slides for moving thesame relative to said guide members, said last-name" means includingclutch mechanism whereby one of said slides may be moved independentlyof the other.

10. A back gauge for shears having a movable blade provided with ashearing knife adapted to cooperate with a stationary shearing knife,said gauge comprising a guide member, means adapted for pivotallyconnecting one end of said guide member to the movable blade of theshears, abutment member su ported by said guide member for movementtoward and from the front of the movable blade, said abutment membeingadapted to normally project in the path of work to be sheared as it isinserted between the knives of the shears, and means operativelyconnected to sai member for moving the other end of guide member aboutsaid pivotal connection whereby said abutment member may be moved to aninoperative position at one side of path.

11. A back gauge for shears having a movable blade provided with ashearing knife adjacent to its lower front edge adapted to cooperatewith a; stationary shearing knife, said gauge comprising a guide member,means adapted for pivotally connecting the front end of said guidemember to the movable blade of the shears, an abutment member supportedby said guide member for movement towardand from the front of themovable blade, said abutment member being adapted to normally project inthe path of work to be sheared as it is inserted between the knives ofthe shears, and means for raising the rear end of said guide memberwhereby said abutment member may be moved to an inoperative positionabove said path.

12. A back gauge for shears having, a housing supporting a stationaryshearing knife, a movable blade provided with a shearing knife adjacentto its lower front edge, and means for adjusting the clearance betweenthe shearing kinves, said gauge comprising a pair of guide members,means pivotally connecting said guide members to the movable blade, apair ofslides supported by sa ide members for movement, toward and fromthe front of said movable blade, an abutment member carried by saidslides and adapted to normally project in the path of work to be shearedas it is inserted between the knives of the shears, means for adjustingsaid abutment member relative to said blade including mecha-- nismindicating the position of said abut ment member with respect to thecutting edge of the stationary shearing knife, settable meanscompensating, so" ndicating mechanism. for different knife clearanceadjustments, and means for raising said guide members whereby the saidabutment member may be moved to an inoperative position above said pathwithout disconnecting said adjusting means and indicating mechanism.

13. A back gauge for shears having housing supporting a stationaryshearing knife and a movable blade provided with a shearing knifeadjacent to its lower front edge, said gauge comprising a pair of guidemembers, means adapted for pit-*otaliy connecting the front ends of saidguide members to the movable blade, a pair of slides supported by saidguide members for movement toward and from the front of said movableblade, an abutment member carried by said slides and adapted to normallyproject in the path of work to be sheared as it is inserted between theknives of the shears, means for raising, the rear ends of said guidemembers whereby said abutment member may be moved to an inoperativeposition, means common to both of said slides for moving the samerelative to said guide members and including mechanism whereby one ofsaid slides may be moved independently of the other, and means forindicating the position of said abutment member with respect to thecutting edge of the stationary shearing knife.

14. In shears of the character described, the combination of a housingadapted to support a stationary shearing knife, a movable blade adaptedto have a shearing knife connected to the front thereof for cooperationwith saidstationary shearing knife, a pair of spaced guide membersconnected to said blade, an abutment member supported by said guidemembers for movement toward and from the front of said blade, saidabutment member being adapted to project in the path of work to besheared inserted between said knives, operating means for adjusting theposition of said abutment member along said guide members includingseparate lead screws rotatably supported by each guide memher andoperatively connected to said abutment member, a common rotatable shaftfor actuating said lead, screws,; means for selectively preventingactuation of one ofsaid lead screws by saidshaft withoutinterfering withthe actuation of the other of said lead screws thereby, and meansoperatively associatedwith said shaft for indicating the position ofsaid abutment with respect; to; the cutting edge: of the stationaryshearing knife, saidlast mentioned, means including a first indicatingdial having graduatio-ns thereon indicating large units of measurementand a second indicating dial having graduations. thereon indicatingsmallunits, of measurement, said sec-- 0nd indicating dial being rotatablerelative to said shaft and, cperatively connected therewith throughgearing.

15. In shearsgof the, character described, the combination of a housingadapted to support a stationary shearing knife, a movable bladeadaptedto have a shearing knife connected to the front thereof forcooperation withsaid stationary knife, a guideimember connected to saidblade, an abutment member supported by said guide member for movementtoward and from the front of said blade; said abutment member beingadaptedto project in the path of work to besheared inserted between saidknives, means including a rotatable shaft operatively connected. withsaid abutment member for adjusting the position of the latter withreference to said blade, and means for fixing the position of saidabutment member in any adjusted position including a friction lockselectively engageable with said 16. In shears, of the characterdescribed, the combination of a housing adapted to support a stationaryshearing knife, a movable blade adapted to have a shearing, knifeconnected to the frontv thereof for cooperation with said stationaryshearing knife, a guide member connected to said blade, an abutmentmember supported by said guide member for movement toward and from thefront Of said blade, said abutment member I being adapted to projectinthe path of work to be sheared inserted betweensaid knives, meansincluding a rotatable,shaftoperatively connected with said abutmentmember for adjusting the position of the latter toward and from thefront of said blade, means for fixing the position of,

said abutment member in any adjusted position,

the lower front edge; thereof for cooperation with,

a stationaryknife, a pair of guide members pivotally connected tosaidblade and extending rear wardly of the front thereof, a pair ofslides supported by said guide. members for movement toward: and fromthe front of said blade, an abutment nzember carried by said slides andadapted to project in the path of work to be sheared inserted betweensaid blades,,operating means common to both of said slides for movingsaid slides relative to said guide members, said means including a driveshaft adjacent to and extending generally parallel with the front ofsaid blade, a

reversible electric motor operatively connectedto said drive shaft, andspeedand directional controls operatively connected to said motor.

18. In shears of. the character described, the

